Question

Work out size of angle x

Answer 1

X=63

Explanation: Add the two given sides, you get 27, since the triangle is a right angle you would subtract 27 from 90.
90-27=63

Answer 2

Explanation:

Comment

You are given values for the adjacent side of <x and the hypotenuse of a right triangle. This defines the Cosine of an angle

Equation

Cos(x) = a/c the way you have labeled it.

Givens

a = 9

c = 18

Solution

Cos(x) = a / c

Cos(x) = 9 / 18

cos(x) = 1/2

x = cos-1(1/2)

x = 60 degrees

Answer

x = 60